Paul Pillar

The Forgotten Principles of Deterrence

An irony of how the events in Ukraine and the associated altercation with Russia have thrown many commentators and policy critics into a Cold War mode is that those same commentators and critics seem to have forgotten (or never learned) much relevant doctrine that was developed and honed during the real Cold War. The doctrine in question embraces many principles involving any attempt to exert power and to exercise influence over other states. The most relevant aspects of doctrine involve deterrence—using threats to dissuade someone from doing something we do not want done—as well as some related concepts also involving coercive methods of trying to influence an adversary's behavior.

Sophisticated treatment of these topics can become somewhat complicated, getting into such matters as multiple levels of deterrence and stability-instability paradoxes. But what much of the commentary on current issues ignores is really rather simple. It is stuff that should be apparent upon careful but straightforward thinking about the objectives, costs, and benefits that apply to the people on the other side of a conflict. Although applications of the principles have endless variations, the principles themselves are immutable. Probably what is still the clearest statement of them came during the height of the Cold War from Thomas Schelling, who received the Nobel memorial prize in economics largely for that work.

One major point of doctrine that has been routinely ignored in the recent commentary is that successful deterrence depends on much more than just the reputation of the deterring state and its demonstrated willingness to use coercion. It depends at least as much on characteristics of the particular conflict, including how much of a stake each side feels it has in it. We should have learned this lesson with the Vietnam War. The United States went so far in demonstrating its willingness to use costly force that it built up an army of over a half million in Vietnam and fought so long that it suffered over 50,000 combat deaths. But it was unable to deter the regime in the north from waging continued war in the south because the nationalist objective of uniting a Vietnam free of foreign domination was much more important to that regime than the United States's objectives in Vietnam were to it.

I have commented previously on the fallacious nature of the notion that for the United States not to take up a gauntlet in one conflict makes it more likely that some adversary in an unrelated conflict elsewhere on the globe would do aggressive things that it would not otherwise have done. Yet that notion persists, most recently in the assertion that Vladimir Putin would not have seized Crimea if the United States had only shown more toughness elsewhere. For many, of course, such an assertion is just one more disingenuous way for Barack Obama's political opponents to bash him. But the notion gets repeated so often that many who hear it, and at least some who say it, probably believe it.

This mistaken belief is related to another erroneous notion about deterrence, which is that taking coercive action against an adversary provides deterrence, rather than making such action conditional on the adversary doing certain carefully defined things we do not want him to do. Senator John McCain exhibited this mistake when he bemoaned how the modest steps the Europeans have taken in response to the situation in Ukraine would not deter Putin. He's right about that, but not because, as he further comments, commercial interests of the Europeans keep them from implementing harsher measures now. From exactly what are we trying to deter Putin? He says he has no intention of seizing any more of Ukraine after Crimea. We may have good reason to worry about the possibility that he might do so anyway, but he has not done so yet. Unconditionally imposing costs when he has not yet done so may satisfy political and other urges on our side, but it lacks deterrence value.